Lith-type emulsions containing a polyalkyleneoxy polymer and a 3-pyrazolidone developing agent



United States Patent 3,518,085 LITH-TYPE EMULSIONS CONTAINING APOLYALKYLENEOXY POLYMER AND A 3-PYRAZOLIDONE DEVELOPING AGENT Kirby M.Milton and Charles A. Golfe, Rochester, N.Y., assignors to Eastman KodakCompany, Rochester, N.Y., a corporation of New Jersey No Drawing. FiledSept. 23, 1965, Ser. No. 489,736 Int. Cl. G03c 5/24, 1/28, 1/04 US. Cl.96--66.3 23 Claims ABSTRACT OF THE DISCLOSURE High contrast photographicemulsions in which the silver halide comprises at least 50% silverchloride are improved by the addition of a polyalkyleneoxy polymer and a3-pyrazolidone silver halide developing agent. Further improvement isobtained by the incorporation of a vinyl polymer and an onium salt.

This invention relates to high-contrast, silver-halidesensitizedphotographic materials for graphic arts use and particularly tolith-type silver halide emulsion layers of improved physical andphotographic properties.

In the photomechanical arts, photographic films capable of providinghigh image contrast and good dimensional stability with varyingtemperature and humidity are required for the preparation of the lineand halftone film intermediates which are used in making printingplates. In reproducing continuous tone material, it is customary to makea halftone photographic intermediate, usually a film negative, in whichthe gradations in tone are represented by differing sizes of dots ofuniform density. The shape, density and uniformity of the halftone dotsare closely correlated to the quality of the resulting picture.

Most lith films are processed in hydroquinone-type developers whichcontain relatively low concentrations of sulfite ion. The dot qualityand the development contrast obtained in processing lith emulsions insuch developers can be improved by processing in the presence of certainwater-dispersible polymers containing substantial proportions ofethylene oxide units, such as polyethylene oxides, their terminallysubstituted derivatives, block copolymers containing ethylene oxideunits, etc. These can be added either to the photographic element or thedeveloping solution or both.

It is further advantageous to use as part of the colloid binder for lithtype emulsions a colloid-compatible vinyl polymer, the presence of whichimproves the dimensionable stability of the resulting lith film.

The marked improvement resulting from the use of the ethylene oxidepolymer on the contrast and dot quality of the emulsion and that of thevinyl polymers on the dimensional stability of the element may result incertain unwanted effects on other properties such as decreasing thedeveloping rate, impairing the emulsion speed, and narrowing thedevelopment latitudes.

There is accordingly a need for a lith film system which will providethe advantages afforded by the above two types of addenda without thepossibility of detrimental 3,518,085 Patented June 30, 1970 results andwhich will produce measurable and simultaneous improvements in (1)physical properties, e.g., dimensional stability and emulsion hardness,(2) photographic properties, e.g., exposure latitude, sensitivity,contrast, line and dot quality, and (3) processing characteristics,e.g., development rate and development latitude.

We have found a method of overcoming the undesirable side effects ofadding polymers to the gelatin of lithtype emulsions without impairingtheir beneficial action.

It is an object of this invention to provide a photographic lith-typesilver halide sensitized film of high dimensional stability, whichyields high contrast, excellent dot quality, high emulsion speed, whichdevelops uniformly in short developing times, and which shows superiorexposure and development latitude.

It is a further object to provide lith-type films containing acompoundwhich reduces the adverse effect of prolonged developmentinduction times which may be required when certain vinyl polymers areused to improve dimensional stability. It is a further object to providelith-type films containing a compound which regains the effectivephotographic speed lost when certain ethylene oxide polymers are used toimprove contrast and dot quality.

It is a further object to provide lith-type films containing a compoundwhich produces, synergistically in combination with certain ethyleneoxide block copolymers, improved speed, contrast and dot quality.

It is also an object to provide improvements in the development ofsilver halide images.

It is a further object to provide a photographic lith film with improvedproperties which can be processed in a simple lith-developer containinga sufficiently high concentration of sulfite ion to provide goodresistance to aerial oxidation by the developer.

It is a further object to provide lith-type films containing a compoundwhich reduces the adverse eifect on emulsion hardness which may beproduced by certain ethylene oxide polymers used to improve contrast anddot quality.

We have accomplished these and other objects which will be apparent fromthe further disclosures and the claims by adding a 3-pyrazolidonecompound to lith-type silver halide sensitized photographic materialscontaining polymeric addenda for the purpose of improving photographicproperties.

Our invention provides an improved photographic lithtype film materialcomprising a radiation sensitive hydrophilic colloid silver halideemulsion, an alkyleneoxy polymer, and a S-pyrazolidone.

In one embodiment of this invention an aqueous silver chlorobromoiodidelithographic emulsion containing at least 50% silver chloride and areduced amount of gelatin is prepared in a manner familiar to thoseskilled in the art. To this emulsion are then added a gelatin-compatiblevinyl polymer, a polyalkyleneoxy compound and a pyrazolidone silverhalide developing agent. This preparation is then coated on a suitablefilm support, dried, sensitometrically exposed, processed in a lith-typedeveloping solution, fixed and dried.

The fine grain silver halide emulsions used to advantage have silverhalide crystals preferably containing at least 50 mole percent chloride.The emulsions can be prepared as described by MacWilliam US. 2,756,148,issued July 24, 1956. These emulsions may be used without beingsensitized, however, it is advantageous to spectrally sensitize themaccording to methods Well known in the art to make them ortho-sensitizedor panchromaticallysensitized.

The silver halide is dispersed in hydrophilic colloid materials used asbinders, including gelatin, collodion, gum arabic, cellulose esterderivatives, such as, alkyl esters of carboxylated cellulose, hydroxyethyl cellulose, carboxy methyl hydroxy ethyl cellulose, syntheticresins, such as the amphoteric copolymers described by Clavier et al. inUS. Pat. 2,949,442, issued Aug. 16, 1960, polyvinyl alcohe], and otherswell known in the art. Examples of these polymeric gelatin substitutesare copolymers of allylamine and methacrylic acid; copolymers ofallylamine, acrylic acid and acrylamide; hydrolyzed copolymers ofallylamine, methacrylic acid and vinyl acetate; the copolymers ofallylamine, acrylic acid and styrene; the copolymers of allylamine,methacrylic acid and acrylonitrile; alkyl acrylate-acrylic acidcopolymers, e.g., copolymers of butyl acrylateacrylic acid; etc., andetc.

Useful compatible vinyl polymers include the following:

(1) Copolymers of butylacrylate and acrylic acid such as those disclosedin U.S. Pat. 3,062,674.

(2) Interpolymers of acrylic acid, unsaturated carboxylic acid esters,and sulfobetaines such as those disclosed in U.S. Ser. No. 449,879 filedApr. 21, 1965, now US. Pat. No. 3,411,912.

(3) Interpolymers of alkyl esters of unsaturated carboxylic acid withsulfoesters of unsaturated carboxylic acids such as those disclosed inUS. Ser. No. 454,683 filed May 10, 1965, now Pat. No. 3,411,911.

(4) Homopolymers of acrylic acid esters, homopolymers of ot-hydrocarbonsubstituted acrylic acid esters. Copolymers of unsubstituted orsubstituted acrylic acid esters with other vinyl compounds, containingat least 90% by weight of acrylic acid ester structural units such asthose disclosed in British Pats. 955,191 and 961,490.

The vinyl polymers are incorporated in the photographic elements of ourinvention at quantities ranging from approximately 30 to 80 percent ofthe total emulsion vehicle. In one embodiment in which a gelatinemulsion is employed, the ratio of gleatin to vinyl polymer ranges from20:80 to 80:20 parts by weight.

Other vinyl polymers useful in our invention may include those disclosedin U.S. Pats. No. 1,933,052, patented Oct. 31, 1933 and No. 2,140,048,patented Dec. 13, 1938 and US. AlienProperty Custodian Ser. No. 397,138,published May 11, 1943.

The alkyleneoxy polymers useful in tihs invention are:

(1) Water-dispersible polyethylene oxides having molecular weights offrom approximately 400 to approximately 4,000. Particularly usefulpolyethylene oxides include the following:

M.W. Polyethylene glycol 400 Polyethylene glycol 600 Polyethylene glycol425 Polyglycol 1000 Polyglycol 4000 These compounds may be expressed bythe general formula:

HOCH CH O (CH O CH CH OH wherein n is an integer greater than 10.

Other useful polyglycols include, for example, polyethylene glycol oleylether, polyethylene glycol ether, as well as the polyethylene glycolsdisclosed in US. Pats. Nos. 2,531,832, 2,423,549, and 2,886,437.

(2) Water-dispersible alkyleneoxy block copolymers containing at leastabout 30 percent by weight of ethyleneoxy units. Particularly usefulwater-soluble block polymers include those block polymers in which thepolyoxypropylene chain (or moiety) has an average molec- 4 ular weightbetween 800 and 3,000 and in which the polyoxyethylene units constitutefrom about 10 to about 70 percent by weight of the polymer.

The water-soluble block polymers of polyoxypropylene and polyoxyethyleneused to advantage inc ude those represented by the formula:

wherein Y represents an organic radical having a valence of x, saidradical being the residue of an organic compound containing atomsselected from the class consisting of carbon, hydrogen, oxygen, nitrogenand sulfur with x active hydrogen atoms, such as, the residue ofpolyhydroxy compounds, e.g., ethylene glycol, 1,2-propanediol, 1,5pentanediol, 1,2,3 propanetriol, sucrose etc., the residue of apolybasic acid, e.g., oxalic acid, malonic acid, succinic acid, maleicacid, citric acid, etc.,

the residue of a polyamine, e.g., ethylenediamine, 1,3-diaminopropylene,etc., the residue of a polyamide, e.g., malonamide, succinamide, etc.,the residue of a polythiol, e.g., 1,2-ethylenedithiol,1,3-propylenedithiol, etc., 11 is an integer greater than 1; x is aninteger greater than 1, so that the values of n and x are such that themolecular weight of the said polymer exclusive of Y, E and R is between800 and 3,000; E represents a polyoxyethylene chain constituting fromabout 10 to about 70 percent by weight of said block polymer; and Rrepresents the hydrogen atom, an alkyl group having from 1 to 20 carbonatoms, (such as methyl, propyl, decyl, dodecyl, octadecyl, etc.), analkyl carbonyl group in which the alkyl groups has from 1 to 20 carbonatoms as described above, an aryl carbonyl group, such as, benzoyl,p-methyl benzoyl, etc.

Included among the preferred block polymers are those having theformula:

in which b represents an integer of from 14 to 42; a and c are eachintegers such that the sum of a+c has a total of from 4 to 48 and thepolyoxyethylene groups constitute between 10 and 70 percent by weight ofthe block polymer.

The block polymers of Formula II and of Formula I where R represents thehydrogen atom are described in Lundsted US. Pat. 2,674,619, issued Apr.6, 1954 and Lundsted US. Pat. 3,022,335, issued Feb. 20, 1962. The blockpolymers of Formula I in which R is hydrogen are readily converted tocompounds where R represents an organic residue by reaction with theappropriate reagent in a suitable inert organic solvent that ispreferably anhydrous. For example, alkyl halides, such as alkylchlorides, alkyl bromides, etc., are used to advantage to replace theterminal hydrogen atom of the block polymer with an alkyl group.Alkyl-p-toluenesulfonates are also used to advantage to place an alkylgroup at the end of the block polymers. The appropriate acid chloride oracid anhydride, such as, acetyl chloride, propionyl chloride, stearoylchloride, benzoyl chloride, acetic anhydride, etc., are used toadvantage to prepare block polymers of Formula I in which R is an alkylcarbonyl or an aryl carbonyl group.

(3) Water dispersi ble alkyleneoxy block copolymers containing at leastabout 30 percent by weight of ethyleneoxy units and containing in theirmain chain up to approximately 15 percent by Weight silicone atoms.Particularly useful water-soluble organosilicone polyalkylene oxidepolymers include those disclosed in US. Pat. No. 2,917,480, issued Dec.15, 1959. Polymers used to advantage are of the type which are preparedby reacting a dialkyl siloxane with a compound of the followingstructure:

wherein Y is the residue of an organic compound containing therein, xactive hydrogen atoms, and wherein n is an integer, x is an integergreater than 1, the values of n and x are such that the molecular weightof the compound exclusive of E and R is between 800 and 3,000, and E isa polyoxyethylene chain constituting 70% by weight of the compound, R ishydrogen or the residue of an organic compound containing an activehydrogen atom; e.g., alcohols, amines. acids, amides, phenols, etc.

The above alkyleneoxy block copolymers (2 and 3) have molecular weightsranging from approximately 600 to about 10,000.

The alkyleneoxy polymers may be added to the photographic element at anystage in the preparation. They may be added as such or from an aqueoussolution or from an organic solvent, e.g., ethanol, but areadvantageously added from solutions in water. They are added to theaqueous hydrophilic colloid (either with or without the silver halide)before it is coated. The alkyleneoxy polymerscan be used to advantageover a wide. range of concentrations. The operable range ofconcentrations is from 0.01 to 3.00 gram of polymer per mole of silver,while the particularly useful range is from 0.010 to 1.0 gram per moleof silver. The optimum concentration of a given alkyleneoxide-containing polymer used in my elements depends upon the resultsdesired, the particular silver halide emulsion, the developer solution,etc., and is readily determined by methods known in the art. Thedetermination of the optimum concentration is preferably made byemploying the alkyleneoxy polymer in the silver halide emulsion layer orin an adjacent hydrophilic colloid layer according to the element thatis desired.

It is advantageous to add certain onium Salts, such as, quaternaryammonium salts, sulfonium salts and phos phonium salts to ourlight-sensitive emulsions in order to increase the photographic speedWithout adversely affecting the improved dot quality, contrast andevenness of development. Examples of quaternary ammonium salts includenonyl pyridinium perchlorate, hexoxymethyl pyridinium perchlorate,ethylene bis-dioxymethyl pyridiniurn perchlorate and others described byCarroll U.S. 2,271,623, issued Feb. 3, 1942, hexadecamethylene-l,l6-bis(pyridinium perchlorate), 9,l6-diaza-7,18-dioxa-8,l7-dioxotetracosane 1,24 bis(pyridinium perchlorate), and others of Beaverset al. U.S. 2,944,898, issued July 12, 1960. Other examples include theonium salts of polyoxyalkylenes of Carroll et al., U.S. 2,944,902,issued July 12, 1960, the polyonium salts of Carroll et al. U.S. 2,288,-226, issued June 30, 1942, such as bis(lauryl methyl sulfonium p-toluenesulfonate) 1,2-ethane, N,N-trimethylene dioxymethyl pyridiniumperchlorate, etc., the sulfonium salts of Carroll et al. U.S. 2,275,727,issued Mar. 10, 1942, such as, n-decyl dimethyl sulfonium p-toluenesulfonate, n-nonyl dimethyl sulfonium p-toluene sulfonate, etc., and thephosphonium salts of Carroll et al. U.S. 2,271,622, issued Feb. 3, 1942,such as, tetramethylene bis-triethyl phosphonium bromide,lauryltriethylphosphonium bromide, etc.

The onium salts are added to the photographic materials atconcentrations ranging from approximately 0.01 to approximately 2.0 gramper mole of silver in the light sensitive emulsions. The preferred rangeis from approximately 0.035 gram to approximately 0.65 gram per mole ofsilver.

The use of the onium compound alone does not result in any particularimprovement in speed in lith emulsions containing vinyl polymers andethyleneoxy polymers.

The addition of 3-pyrazolidone to the emulsion containing the oniumsalt, however, gives a very surprising increase in emulsion speed andthis is enhanced further by some apparent synergism between the3-pyrazolidone and an onium compound. The pyrazolidones used toadvantage 6 include those disclosed in U.S. Pat. No. 2,751,297 andrepresented by the following general formula:

XN CHRI l-phenyl-3-pyrazolidone 1-p-tolyl-3 -pyrazolidone5-phenyl-3-pyrazolidone 5-methyl-3-pyrazolidone1-p-chlorophenyl-3pyrazolidone l-phenyl-5-phenyl-3-pyrazolidonel-m-tolyl-3-pyrazolidone l-phenyl-5-methyl-3-pyrazolidone1-p-tolyl-5-phenyl-3pyrazolidone 1-m-tolyl-3-pyrazolidone1-p-methoxyphenyl-3pyrazolidone 1-p-acetamidophenyl-3-pyrazolidone I1-phenyl-2-acetyl-4 4-dimethyl-3 -pyrazolidone 1-phenyl-44-dimethyl-3-pyrazolidone 1-m-aminophenyl-4-methyl-4-n-propyl-3-pyrazolidone 1-o-chlorophenyl-4-methyl-4-ethyl-3pyrazolidone1-m-acetamidophenyl-4:4-diethyl-3pyrazolidone l-(p-fi-hydroxyethylphenyl) -4 4-dimethyl-3-pyrazolidonel-phydroXyphenyl-4 4-dimethyl-3-pyrazolidone 1-p-meth0xyphenyl-4:4-diethyl-3 -pyrazolidone 1-p-tolyl-4 4-dimethyl-3-pyrazolidone 1 (7hydroxy 2 naphthyl) 4-methyl-4-n-propyl-3- I pyrazolidone 1-p-diphenyl-44-dimethyl-3-pyrazolidone 1-(p-B-hydroxyethylphenyl)-3-pyrazolidonel-o-tolyl-3-pyrazolidone l-o-tolyl-4 4-dimethyl-3-pyrazolidonel-benzothiazolyl-3-pyrazolidone 4-methyl-1-phenyl-3-pyrazolidone Usefulconcentrations of pyrazolidones in the photographic elements range from0.005 to 2.0 gm./mole of silver in the emulsion. The preferred range isfrom 0.01 to 1.0 gm./mole of silver. Optimum concentrations of thealkyleneoxy polymers and the pyrazolidones can be determined readily byactual tests in the emulsion and will vary with the formulation ofthephotographic emulsion and the developer used.

In general, both the alkyleneoxy polymer and the pyrazolidone areincorporated in the light-sensitive silver halide emulsion. While thisis a particulary useful form of the invention, either or both thealkyleneoxy polymer and pyrazolidone may alternatively be present in anadjoining insensitive layer, or one or both can be imbibed from aprocessing bath, it being required only that both are present duringdevelopment.

Our light-sensitive emulsions can be coated to advantage on any of theconventional photographic supports, including glass, cellulose acetate,polystyrene, polyalkyleneterephthalate, etc.

A typical lith-type developing solution which may be used contains asthe only developing agent, hydroquinone or a hydroquinone derivative andhaving a very low sulfite ion content, the sulfite ion content beingmaintained by the presence in the solution of formaldehyde. Lith-typedeveloping solutions are used for developing lithographic film materialswhich contain photographic emulsions having an emulsionsof uniform andfine-grain silver halide crystals. Such emulsions are developed inlith-type developing solutions to yield a contrast of 10 and above.

A typical lith-type developing solution is Kodak De- The film sampleswere then fixed, washed and dried, and the speed, contrast, fog and dotquality evaluated. A dot quality scale from 1 to 10 representsincreasing quality of half-tone dot with increasing number, 6 being afirst acceptable quality of half-tone dot. The results are illustratedin Table I.

veloper D-85 (see Kodak Formulas for the Graphic Arts, Kodak PamphletNo. Q41, p. 4) as follows:

KODAK DEVELOPER D-85 I Water about 90 F. (30 C.) metric cc 500 Sodiumsulfite desiccated grams 30.0 Paraformaldehyde do 7.5 Sodium bisulfitedo 2.2 Boric acid crystals do 7.5 Hydroquinone do 22.5 Potasium bromide.Q. do 1.6

Water to make 1.0 liter. A

The following examples are intended to illustrate our invention but notto limit it in any way:

EXAMPLE I A high-contrast ortho-senitized fine-grain gelatinochlorobromoiodide emulsion containing 90 mole percent 35 The results areillustrated in Table II.

silver chloride, 9 mole percent silver bromide, and ap- It is shown thatthe addition of PEO, oleyl ether of polyethylene glycol having amolecular weight of 1540, raised contrast, dot quality, but caused speedloss. Further addition of Elon did not regain speed loss.

EXAMPLE II Example I was repeated, except that the methyl-paminophenolwas replaced by 4-methyl-l-phenyl-B-pyraz olidone as shown below:

(a) no further addition I '(b) 0.5 gm. PEO, oleyl ether of polyethyleneglycol having a molecular weight of 1540 (c) 0.5 gm. PEO, oleyl ether ofpolyethylene glycol having a molecular weight of 1540, plus .025 gm.4-methyl- 1-phenyl-3-pyrazolid0ne (d) 0.5 gm. PEO, oleyl ether ofpolyethylene glycol having a molecular weight of 1540, plus .050 gm.4-methyl- 1-phenyl-3-pyrazolidone TABLE II 2V minutes developing time 3%minutes developing time Relative Effective D ot Relative Efleetive Dotspeed contrast quallty Fog speed contrast quality Fog proximately 1 molepercent silver iodide was prepared and split into separate portions. Thefollowing compounds were added to the individual portions in theindicated amounts per mole of silver halide:

(a) no further addenda (b) 0.5 gm. PEO, oleyl ether of polyethyleneglycol having a molecular weight of 1540 (c')" 0.5 gm. PEO, oleyl etherof polyethylene glycol having a molecular weight of 1540 plus 0.025 gm.methylp-aminophenol (d) 0.5 gm. PEO, oleyl ether of polyethylene glycolhaving a molecular weight of 1540 plus 0.050 gm. methylp-aminophenol M pThevarious parts were coated on acellulose triacetate film support at acoverage of 455 mg. of silver halide and 1.450 mg. of-vehicle per squarefoot, dried, exposed to continuous and half-tone screen step wedges,developed for 2% minutes and 3%.minutes, respectively, at a temperatureof 68 F. in a developing solution of the following composition: H

Hydroquinone 15.0 Sodium formaldehyde bisulfite 50.0 Sodium bicarbonate22.5 Sodium carbonate 35'.0 Sodiumsulfite 2.5 Potassium bromide 0.75.

Water to make 1 liter.

It is shown that the addition of PEO, oleyl ether of polyethylene glycolhaving a molecular weight of 1540, raised contrast and dot quality butcaused speed loss. Further addition of a 3-pyrazolidone regained speed,maintained contrast and dot quality.

EXAMPLE III An emulsion was prepared as described in Example I. Thefollowing compounds were added to the individual portions in theindicated amounts per mole of silver halide.

TABLE III [DEVELOPING TIME: 1% MINUTES] Relative speed Efieetivecontrast Sample a 100 55 b 741 6. 3 e. 289 2. 4

EXAMPLE IV TABLE IV [DEVELOPING TIME: 2% MINUTES Relative speedEffective contrast Control. 194 5. 4 Sample containing 4-methyl'1-phenyl-Ekpyrazolidone 253 11. 2

Result: 4-methyl-l-phenyl 3 pyrazolidone has increased speed andcontrast.

EXAMPLE V An emulsion was prepared as in Example IV and split into twoportions, (a) and (b). To each portion were added, per mole of silverhalide, .030 gm. of organosilicone,coply(polyethyleneoxypolypropyleneoxy dimethylsiloxane), mol weight2000, PPG-PEG 6040, 9.5% by weight silicone. To portion (b) was added,in addition, .015 gm. of 4-methyl-1-pheny1-3-pyrazolidone per mole ofsilver halide. Each sample was processed and evaluated as in Example I.The results are shown in Table V.

TABLE V [DEVELOPING TIME: 1% MINUTES] Relative speed Efiective contrastResult: The 3-pyrazolidone has increased speed and contrast.

EXAMPLE VI An emulsion was prepared as in Example IV and split into twoportions, (a) and (b). To each portion were added, per mole of silverhalide, 0.100 gm. of an organosilicone, a water-soluble polysiloxanemade up of dimethyl silicone sections and polyether sections andcontaining 6.5% by weight of silicone, and .5 gm. ofw-hydroxydecylpyridinium-perchlorate. To portion (b) were added, inaddition, .015 gm. of 4-methyl-l-phenyl-3-pyrazolidone. Each sample wasprocessed and evaluated as in Example I. The results are shown in TableVI.

TABLE VI.-DEVELOPING TIME: 2 MINUTES Relative speed Efieetive contrastResult: Addition of an onium salt, a known developer accelerator, hasgiven acceptable speed, but has lowered contrast. Addition of4-methyl-1-phenyl-3-pyrazolidone has improved speed further and givenexcellent contrast.

10 EXAMPLE v11 .This is a repeat of Example VI, except that Sample (a)contained only 0.085 gm. of the organosilicone of Example VI.

The results are shown in Table VII.

TABLE VIL-DEVELOPING TIME: 2 MINUTES I Relative speed Effective contrastResults: Same as in Example VI.

EXAMPLE VllII An emulsion was prepared as in Example IV and split intothree portions, (a), (b), and (c). To portion (a) were added per mole ofsilver halide, .025 gm. of a block copolymer of polyethyleneoxide andpolypro'pyleneoxide units having a total molecular weight of 2000 andwherein the molecular weight of the polypropyleneoxide constituent is1200 and wherein the ratio by weight of the polyethyleneoxide topolypropyleneoxide is 60 to 40; to portion (b), .025 gm. of a polymersimilar to (a) above, having a total molecular weight of 2920 andwherein the molecular weight of the polypropyleneoxide constituent is1750 and wherein the ratio by weight of the polyethyleneoxide topolypropyleneoxide is 40 to 60; to portion (c), .055 gm. of apolypropyleneoxide-polyethyleneoxide glutarate having a total molecularweight of 2000 and wherein the ratio by weight of polyethyleneoxide topolypropyleneoxide is 60 to 40' and wherein the polypropyleneconstituent has a molecular weight of 1200. To each portion were added,in addition, .015 gm. of 4-methyl-1- phenyl-3-pyrazolidone and .3 gm. ofw-hydroxydecyl pyridinium-perchlorate. Each sample was processed andevaluated as in Example I. The results are shown in Table VIII.

Result: All coatings showed excellent speed and good contrast.

EXAMPLE IX An emulsion was prepared as in Example I wherein the vehiclecomprised, per mole of silver halide, 70 gm. of gelatin and 70 gm. ofcopoly(butyl acrylateacrylic acid- 4,4,9 trimethyl8-oxo-7-oxa-4--azonia-9-decene-l-sulfonate). The emulsion was split intotwo portions, (a) and (b). To each portion were added, per mole ofsilver halide, .075 gm. of the block polymer A of Example VIII and .500gm. of w-hydroxydecyl pyridinium-perchlorate. To portion (b) were added,in addition, .015 gm. of 4- methyl-1-pheny1-3-pyrazolidone. Each samplewas processed and evaluated as in Example I. The results are shown inTable IX.

The advantageous efifeot of the 3-pyrazolidone with respect to speed andcontrast is retained when the vinyl polymer concentration in theemulsion vehicle is increased to constitute 50 percent of the totalvehicle.

EXAMPLE X To an emulsion as described in Example I were added, per moleof silver halide, 0.1 gm. of organosilicone block polymer of Example VI.The emulsion was then divided into two portions, A and B. To portion Bwere added,

1 1 per mole of silver halide, 0.015 gm. of 4-methyl-1-ph nyl-3-pyrazolidone. After coating, the above portions of emulsion asdescribed in Example I, samples of each film were processed as describedin Example I at the developing times as shown below: the results arelisted in Table X.

It is shown that the addition of small amounts of 4-methyl-l-phenyl-3-pyrazolidone to silver halide emulsions containingpolyalkylene oxide-dialkyl siloxane polymers results in an increase inspeed, contrast and halftone dot quality over a wide range of developingtime.

EXAMPLE XI One film sample of each coating made with emulsion portions Aand B of Example X was incubated for 1 week at 120 F. and 50% relativehumidity. Each of the incubated samples was, together with anonincubated corresponding sample, immersed at a temperature of 68 F.for 4 minutes into a developing solution of the following composition:

Water ml 500 Methyl-p-aminophenol gm 1.0 Sodium sulfite, dessicated gm75.0 I-Iydroquinone r gm 9.0 Sodium carbonate, monohydrate gm 30.0

Potassium brodide gm 5.0

Water to make 1.0 liter.

The observed fog of each sample is recorded in Table XI.

TABLE XI Fog Fresh test Ineubated sample Coating:

It is shown that the presence of 4amethyl-1-phenyl-3-pyrazolidone haseffectively protected the film material against fog growth uponincubation.

EXAMPLE XII TABLE XII Developing time, Relative Effective min. speedcontrast Coating:

a 2 100 7. 5 b 2 115 10. 5 e 2 186 9. 0

12 EXAMPLE XIII This example illustrates the advantage derived from thepresence of the pyrazolidone in the emulsion over its presence in thedeveloper solution. It also illustrates, again, the superiorty of apyrazolidone over other common developing agents as an addenda in thelith-type materials of our invention.

Several film strips were prepared according to the procedures describedin the preceeding examples. They comprised, in addition to silver halideand other common addenda, the following compounds per mole of silverhalide:

Block polymer A of Example VIII, grams Developer Strip A 0. 0254-methyl-l-phenyl-3-pyrazolidone,

0.015 gm. B 0. 025 Hydroquinone, 0.5 gm. C 0. 025N-methyl-p-aminophenol, 0.5 gm. D 0.025 None.

Strips A, B, and C were developed in the developer solution of ExampleI. Strip D- was developed in the developer soution of Example I to whichwere added 5 gm. of 4-methyl-1-phenyl-3-pyrazoidone per liter ofsolution. The development time was in each case 1% minutes.

Relative Effective Dot spee contrast quality Fog Effective Contrast of adeveloped photographic material differs from the conception of contrastwhich is in the photographic art generally synonymous with only theslope of the straightline portion of the characteristic curve, in thatthe slope of the characteristic curve in the toe region is also takeninto account. For example, two diiferent photographic materials mayexhibit identical contrasts, but the one whose characteristic curveshows also a more acute shape of the curve in the toe region has ahigher effective contrast.

Other tests similar to those described above have shown (a) thatcoatings of lith-type emulsions containing a vinyl polymer for thepurpose of improving dimensional stability require a considerably longerdevelopment time to yield satisfactory dot quality than coatings notcontaining such vinyl polymers and that at such prolonged developmenttimes the vinyl polymer containing coatirigs produced unacceptably highfog, (b) materials as described under (a) which, in addition, containeda 3-pyrazolidone did not exhibit the cited undesirable side effectsintroduced by the vinyl polymer.

The quality of the silver images produced in lithtype emulsion layers isconveniently measured in terms of efiective contrast and dot quality.Dot quality is a measure of the quality of the reproduction of ahalftone image lith-type photographic elements exposed to a half-toneimage, and developed, produce areas commonly referred to as shadow dotsand areas known as highlight areas. Intermediate between these twoextremes are areas of varying size. The dot quality used herein is ameasure of the areas referred to as 50% dots Ge, /2 clear, and V2developed denisty) and is expressed in a progressive scale where 9 isexcellent and 1 is extremely poor. A 50% dot quality below 6 isgenerally not acceptable.

. 13 g The beneficial combination of addenda which constitutes ourinvention are used to particular advantage in lith emissions containingmore than 50 mloe percent of silver chloride. The image reproductionsproduced in our lithographic emulsion layers-are of excellent quality.Although the conventional alkaline, pure hydroquinone, low free-sulfitedeveloper may be used to develop these exposed elementsyit is alsoadvantageous to use a pure hydroquinone developer having 'from to about30 grams of an alkali-sulfiteper liter of developing solution or even anElon-hydroquinone developer having from 10 to about 30 grams of analkali-sulfite per liter of developing solution. When the elements ofthis invention are developed in .one of theitwo latter developingsolutions, not only is the image contrast high and the dot qualityexcellent, but this excellent quality is produced over a wide range ofexposure and development times,

Typical olymeric vinyl compounds useful in our invention are disclosedin.U. S. P at; 3,142,568, issued July 28, 1964, incorporated herein'byL-ref erence'.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that var can beeffected within the spirit and scope of the invention as describedhereinabove and as defined in the appended claims.

We claim: 1

1. A light-sensitive photographic element comprising a support havingthereon at least one light-sensitive silver halide emulsion in which thechloride comprises at least 50 mole percent of the halide, containing ahydrophilic colloid binder, a polyalkyleneoxy polymer in amount of about0.01 gram to about 3.0 grams per mole of silver halide, and a3-pyrazolidone silver halide developing agent in an amount of about0.005 gram to about 2.0 grams per mole of silver halide.

2. A photographic element of claim 1 in which the colloid binder isgelatin.

3. A light sensitive photographic containing an onium salt.

4. A light sensitive photographic element of claim 2 containing anaqueous dispersion of a polymerized vinyl compound.

5. A light sensitive photographic element of claim 2 comprising anaqueous dispersion of a polymerized vinyl compound and an onium salt.

6. A light sensitive photographic element of claim 2 in which saidsupport is a dimensionally stable polymeric support and said elementcomprises an aqueous dispersion of a polymerized vinyl compound and anonium salt.

7. A photographic element of claim 4 in which the ratio of gelatin tovinyl polymer ranges from 20 to 80 to 80 to 20 parts by weight.

8. A photographic element of claim 4 in which the vinyl polymercomprises an acrylic acid-ester polymeric compound selected from thegroup consisting of a homopol mer of an acrylic acid-ester and acopolymer of ac. lic acid-ester and acrylic acid, said copolymercontaining at least 80% by weight of units of said acrylic acid esters.

9. A photographic element of claim 4 in which the vinyl polymercomprises an interpoly-mer selected from the group consisting of acrylicacid, unsaturated carboxylic acid esters and sulfobetaines, saidinterpolymer containing (1) up to about by weight, of acrylic acid, (2)at least about 75%, by weight of a monomer having the formula:

element of claim 2 wherein R is hydrogen or methyl and R is an alkylradiions and modifications 14 cal, containing 1-12 carbon atoms, with(3) up to about 10%, by weight, of a monomer having the formula:

wherein R- is hydrogen or alkyl, R and R are each divalent saturatedaliphatic hydrocarbon radicals, containing up to 12 carbon atoms, and Rand R are each hydrogen or alkyl.

10. A photographic element of claim 1 in which the polyalkyleneoxypolymer is the oleyl ether of polyethylene glycol.

11. A photographic element of claim 1 in which the polyalkyleneoxypolymer is a block polymer of polyoxypropylene" and polyoxyethylenerepresented by the formula: p

wherein Y represents an organic radical having a valence of x; n is aninteger; x is an integer'greater than 1, so that the values of n and xare such that the molecular weight of the said polymer exclusive of Y, Eand R is between 800 and 3,000; B represents a polyoxyethylene chainconstituting from about 10 to about 70 percent by weight of saidpolymer; and R is a member selected from the class consisting, of thehydrogen atom, an alkyl group, an alkyl carbonyl group, and an arylcarbonyl group.

12. A photographic element of claim 1 in which the polyalkyle'neoxypolymer is a block copolymer of polyoxypropylene and polyoxyethylenerepresented by the formula:

wherein b represents an integer of from 14 to 52; and a and c eachrepresent integers such that the sum of a+c represents an integer offrom 4 to 48 and the polyoxyethylene groups constitute between 10 and 70percent by weight of said polymer. 1

13. A photographic element of claim 11 in which the copolymer ofpolyoxypropylene and polyoxyethylene contains in the main chain siliconeatoms at concentration ranges to approximately 15% by weight, of thepolymer compound.

14. A photographic element of claim 12 in which the copolymer ofpolyoxypropylene and polyoxyethylene contains in the main chain siliconeatoms at concentrations ranging up to approximately 15%, by weight, ofthe polymer compound.

15. A photographic element of claim 3 in which the onium salt isselected from the class consisting of a quaternary ammonium salt, asulfonium salt and a phosphonium salt.

16. A photographic element of claim 3 in which the concentration of theonium salt ranges from approximately 0.01 to approximately 2.0 grams permole of silver halide inthe emulsion.

17. A photographic element of claim 1 in which the 3-pyrazolidone isselected from the class represented by the following generic formula:

wherein X represents hydrogen or acetyl, R represents a heterocyclicgroup or an aryl group of the benzene or naphthalene series and Rrepresents hydrogen, an aryl group of the benzene or naphthalene series,or an alkyl group, and R and R each represents hydrogen or an alkylgroup.

IS. A photographic element of claim 4 in which the 15 ratio of gelatinto vinyl polymer ranges from 20 to 80 to 80 to 20 parts by weight.

19. A photographic element of claim in which the polymerized vinylcompound comprises an acrylic acidester polymeric compound selected fromthe group consisting'of a homopolymer of an acrylic acid-ester, and acopolymer of acrylic acid-ester and acrylic acid, said copolymercontaining at least 80% :by weight of units of said acrylic acid-esters.

20. A photographic element of claim 5 in which the polymerized vinylcompound comprises an interpolymer selected from the group consisting ofacrylic acid, unsaturated carboxylic acid-ester and sulfobetaines, saidinterpolymer containing (1) up to about 15%, by weight, of acrylic acid,(2) at least about 75%, by weight, of a monomer having the formula:

wherein R is hydrogen or methyl and R is an alkyl radical, containing1-12 carbon atoms, with (3) up to about by weight, of a monomer havingthe formula:

wherein R is hydrogen or alkyl, R; and R are each divalent saturatedaliphatic hydrocarbon radicals, containing up to 12 carbon atoms and Rand R are each hydrogen or alkyl.

21. A photographic element of claim 15 in which the concentration ofsaid polyethyleneoxy polymer present in said emulsion ranges from 0.001to 3.0 grams per mole of silver halide.

22. A photographic element of claim 15 in which the polyalkyleneoxypolymer is the oleyl ether of polyethylene glycol.

23. A process of developing an exposed photographic silver halideemulsion in which the halide comprises at least mole percent chloride,comprising imbibing into the said emulsion about 0.01 gram to 3.0 gramsper mole of silver halide of a polyalkyleneoxy polymer and about 0.005gram to about 2.0 grams per mole of silver halide of a 3-pyraz0lidonesilver halide developing agent, and reducing the exposed silver halideto silver.

References Cited UNITED STATES PATENTS 3,017,271 11/1962 Piper 9666.3 X3,142,568 7/1964 Nottorf 96-87 3,158,483 11/1964 Lowe et al 96--66.33,312,550 4/1967 Stewart et al 96-76 X 3,294,540 12/1966 'Golfe 96107NORMAN G. TORCHIN, Primary Examiner R. E. FICHTER, Assistant ExaminerUS. Cl. X.R.

